Longer Bluetooth antenna

VIM3
1

Hi,

We have a steel enclosure we need to put the VIM3 pro into and bluetooth signal from the antenna that comes with the board is too short to get a good signal outside the enclosure (40cm).

Do you have any recommended antennas that we could use or bluetooth USB adapters (that work with android?)? I see there are many IPEX antennas with different mhz not sure which is the right one.

Also both antennas say WIFI+BT on the VIM3 pro. Does it matter which one the new antenna will be connected to or do I need to get two?

Thanks

2

Hello, Frequencies are usually 2.4GHz for Bluetooth/WiFi(2.4GHz band) and 5GHz for WiFi(5GHz band).
In my opinion, a single external antenna for the 2.4GHz band would do. Two external antenna would allow the 5GHz WiFi to benefit as well.
However, after viewing the information here, I am not sure, as both IPEX connectors list WiFI&BT.

2160Ă—768

BegGuide
BegGuide1015Ă—154 27.1 KB

Looking at the VIM3 schematic, I believe J9, or the IPEX connector closest to the rear of the VIM3, would be your BT/WiFi.

WiFi-BT-Ant
WiFi-BT-Ant1157Ă—670 110 KB

WiFi-BT-Ant-Drw
WiFi-BT-Ant-Drw793Ă—667 103 KB

You may want to wait for confirmation from the Khadas Team.

4 Likes
3

Thanks. Is it IPEX 1 or IPEX 4 for the connector?

4

I am not sure on this, I have not located that specific information looking through the documentation or literature.
In the schematic above, the IPEX connector is labeled as MHF. I don’t think that is sufficient information.
@Gouwa or other Khadas Team member may need to get that info for you.

@minif If you look at the back of the Antenna’s Ipex plug, mine shows a 13. That leads me to speculate that the mating IPEX connector is 20278-112r-13.
Searching that part number on IPEX site produces this result.

1 Like
5

It’s I-PEX 1

Have fun!

3 Likes
6

Thanks for your help RDFTKV and Gouwa.

7

Here is what I’ve done.

IMG_7008
IMG_70084032Ă—3024 675 KB

5 Likes
8

Wow you must be getting all the networks from around ur house :smiley:
I think this is the best hack, Khadas should start selling such antennas :wink:

Nice hack.

9

Now you can buy these on AliExpress, and they are not quite expensive, but they are very bulky, I think this fact was taken into account by Khadas in production. But I wonder how much the new antennas really helped? :slightly_smiling_face:

10

I wish I could do a comparison but I have broken my original antenna…

11

OK I still had the “B” antenna intact so I plugged it back to the ipex connector marked with “B”, leaving the “W” marked connector unconnected.

Connecting to my wifi router through a weight-holding wall, I got

  • -44 dBm (94%) at 2.4G
  • -65 dBm (64%) at 5G

and my router reported the device was connected using 2.4G.

With my modification, I got

  • -41 dBm (99%) at 2.4G
  • -52 dBm (83%) at 5G

and my router reported the device was connected using 5G. Also my MacBook Pro was placed near the Vim3, and it got similar wifi strength on 5G.

So for 2.4G there was a +3dBm boost and for 5G the difference was 7dBm.

1 Like
12

Additional notes:

I think the biggest advantage of having an external antenna is it can avoid USB3 interference.

I also believe the ipex connectors on the vim3 are somewhat equal. Both of them can handle either 2.4G and 5G signal.